Magnesium L-Threonate: The Form Studied for the Brain
Magnesium L-threonate is the newest of the common forms, developed in 2010 and often sold under the branded ingredient name Magtein. Its pitch is brain delivery: in animal studies it raises magnesium levels in the brain more effectively than other forms, which is why every bottle mentions memory and focus.
The human research hasn’t caught up with the pitch yet. A few small randomised trials have reported improvements on cognitive measures, but the samples are small, several of the trials were funded by the ingredient’s maker, and sleep studies using this form have shown strong placebo effects. Promising is the fair word. Proven isn’t, at least not yet.
Best for: people specifically chasing cognitive goals who don't mind paying more for early-stage science.
Worth knowing: it's one of the pricier forms, and each capsule delivers relatively little elemental magnesium. If raising your overall magnesium is also a goal, check that figure before buying.
Sources: Lopresti & Smith, Frontiers in Nutrition, 2026 (https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1729164/full); magnesium L-threonate sleep RCT, 2024 (https://pmc.ncbi.nlm.nih.gov/articles/PMC11381753/)
This article is general information, not medical advice.